The GE-6550A & the Fender 400-PS Amplifier

From around 1972-73, Rich had been part of the team that worked on the development of the GE 6550A. He worked in association with Harry Storm and Chris McCoulle of General Electric and with Fender head of R&D, Ed Jahns. (Note - Ed had previously worked on the development of the famous 6550 Tung Sol "Coke Bottle.")

Since then, we have gotten back in touch  Harry Storm, and Chris McCoulle, in addition, Bud Ringmann the creator of the 6550A.  These three men were head of the entertainment tube division of General Electric.


A better 6550 was needed for the Fender 400 PS. With the Proto-Type 6550A tubes supplied by GE, Rich was able to produce better than a total average of 560 CLEAN watts RMS into four separate 4 ohm loads for these six tube groups of 6550A's. Mind you, it only took six 6550A tubes in the amplifier to produce this output level. This 400 PS was the Testing & Torture Rig for those Proto-Type GE-6550A's

6550A tube testing on a Fender 400 PS

The 400 PS has melted lesser 6550's. When we say melted, we mean the glass envelope too!  Below are three pictures of a 6550 that came out of a 400-PS that had been setup and biased by one of the Bias Methods suggested in one of the popular Do-It-Yourself amplifier books found in the music stores.  This amplifier is not your everyday run of the mill guitar or bass amplifier; and these book's authors don't even touch on the knowledge required to understand the workings of a 400-PS.

Below is the result of an amp tech who did not have the "experience" or "knowledge" to properly setup a 400-PS.  This type of high powered circuitry is not something for the inexperienced to be fooling around with.  It was one of the today's many "self proclaimed" amp techs that caused the failure that lead to a tube meltdown, and a lot of burnt amplifier components.

There is a 30 step factory setup procedure that requires specific test equipment.  Without this, things like this are guaranteed to happen.

The "Only" Problem with this 400-PS was a combination of User and  Amp Tech Errors.


There is no better 6550 than the GE-6550A.  Here is a 400 GE loaded, and ready to RUMBLE!


We still keep a Fender 400 PS in the shop today. It's still a "Most Amazing Amplifier".

In the above picture you see the Power Transformer on the left side of the chassis and on the right side is not the output transformer, but the driver transformer for the six 6550A's the amplifier uses.  Yes, that is vintage Fender Sea Foam Green we painted the chassis with as an added touch to the restoration of this 400-PS.

Above you now see the output transformer on the left with 6550's driver transformer next to it.  This amplifier has an 84 pound chassis weight, and  the experience of playing through one of these 400-PS amplifiers is worth every pound of iron the transformers are made from.

This is a look at the insides of a 400-PS going through some restoration and re-wiring for the high power modification that will take it up over 560 Clean RMS watts with a fresh set of NOS GE-6550A's in the output tube sockets.

If you happen to be an owner of a 400-PS, please let us know. We are trying to put the history of the 400-PS together. In an effort to help all Fender 400-PS owners we are planning a special page for the "400-PS Club". This is a place where 400-PS owners can meet each other through a clearing house of infomation. We can all share comments, pictures, e-mail links, and posted helpful tips.

Comments and questions on the Fender 400-PS are always invited.


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